docs: add acknowledgements section to README with reference to @distube/ytdl-core

Author: HuakunShen

README.md

@@ -3,3 +3,7 @@
 This extension allows you to download videos from YouTube.
 
 ![Demo Image](https://i.imgur.com/hHtmbny.png)
+
+## Acknowledgements
+
+- [@distube/ytdl-core](https://www.npmjs.com/package/@distube/ytdl-core)